Multi-Point Electrode RF Phase Control for Plasma Uniformity
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Solution Overview
Problem
Plasma fabrication processes in chambers suffer from spatial non-uniformity due to RF power coupling at a single point on the electrode, leading to inconsistent plasma density and material deposition/etching quality across the workpiece surface.
Innovation Solution
Coupling RF power with different phase offsets to multiple points on the electrode, specifically at least four points distributed along orthogonal dimensions, to optimize spatial uniformity of the plasma process, ensuring uniform plasma density and material characteristics across the workpiece.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If RF power is coupled to a single point on the electrode, then the device complexity is reduced, but the spatial uniformity of the plasma process deteriorates
Solution Approach 1:
The electrode is divided into multiple RF connection points (at least four) distributed along orthogonal dimensions, with each point receiving RF power with different phase offsets. This segmentation allows independent control of plasma density at different spatial locations, resolving the contradiction between simple structure and uniform plasma distribution.
Solution Approach 2:
The invention transitions from single-point (0D) or linear (1D) RF coupling to multi-point coupling in two orthogonal dimensions (2D) on the electrode surface. By distributing connection points across X and Y axes and applying phase offsets, the system achieves uniform plasma coverage across the entire workpiece surface, overcoming the limitations of single-point coupling.
2Manufacturing precision
If RF power is coupled to multiple points with different phase offsets, then the spatial uniformity of the plasma process is improved, but the device complexity increases
Solution Approach 1:
The RF power coupling system is segmented into multiple independent coupling points, each with controllable phase offset. This allows precise local control of plasma density while maintaining overall system manageability through modular architecture.
Solution Approach 2:
The invention controls plasma uniformity by adjusting the phase offset parameter of RF power at each connection point. By varying this single parameter across multiple points, the system achieves uniform plasma distribution without requiring complex structural modifications.
3Area of stationary object
If the electrode dimension exceeds one-quarter wavelength of RF power, then the processing area is increased, but the plasma density uniformity deteriorates
Solution Approach 1:
Large electrodes are divided into multiple RF connection zones, each smaller than one-quarter wavelength, with independent phase control. This segmentation maintains plasma uniformity within each zone while extending the overall processing area through coordinated multi-zone operation.
Solution Approach 2:
The invention extends uniform plasma control from one-dimensional linear electrodes to two-dimensional planar electrodes by distributing RF connection points across orthogonal dimensions. This allows large rectangular workpiece surfaces to be processed uniformly despite exceeding the one-quarter wavelength dimension.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces spatial non-uniformity of the plasma process, resulting in more consistent material deposition or etching quality across the workpiece surface, enhancing the overall efficiency and reliability of plasma fabrication.
Implementation Method 1
RF power can be capacitively coupled to plasma within a plasma chamber by coupling a source of RF power to an electrode positioned within, or adjacent to, the plasma chamber
Implementation Method 2
couples RF power with different phase offsets to different RF connection points on an electrode of a plasma chamber
Data Source
AI summary
RF power is coupled with different phase offsets to different RF connection points on an electrode of a plasma chamber. Preferably, the number of different RF connection points and corresponding phase offsets is at least four, and the positions of the RF connection points are distributed along two orthogonal dimensions of the electrode. Preferably, power to each respective RF connection point is supplied by a respective RF power supply, wherein each power supply synchronizes its phase to a common reference RF oscillator.